The first heart sound corresponds in time with
A. Closure of the aortic and pulmonary valves.
B. The P wave of the electrocardiogram.
C. A rise in atrial pressure.
D. A rise in ventricular pressure.
E. The A wave in central venous pressure.
A. False It is synchronous with mitral and tricuspid closure.
B. False It corresponds with the QRS complex.
C. True The mitral and tricuspid valves bulge back into the atria.
D. True This closes the mitral and tricuspid valves.
E. False It corresponds with the C wave; the A wave is due to atrial contraction which precedes the first heart sound.
